A memory device is described in German Patent Application No. DE 43 17 175 A1. European Patent Application No. EP 1 252 627 B1 describes an assemblage for supplying voltage to a volatile semiconductor memory. German Patent Application No. DE 100 03 006 A1 describes an assemblage and method for signal processing and storage in which filter coefficients are stored in a RAM memory region that is separate from a microprocessor.
It is furthermore conventional to store in a separate module (e.g., an EEPROM) nonvolatile data. For this, the data are transferred via a communication line, for example a bus, to said module. Both this transfer and the nonvolatile storage operation require a specific period of time. If the supply voltage to the control unit is interrupted during this period of time, the storage operation is then also interrupted, and the data in the memory module are incomplete and inconsistent. To prevent this, complex actions—for example, multiple storage in the EEPROM, temporary data retention in the application microprocessor—have hitherto been taken under the control of software in the microprocessor on which the applications are running (application microprocessor) to ensure the consistency and completeness of the data. Nevertheless, it is at present impossible to preclude the occurrence of data losses. This can result in field feedbacks and complex error investigations.